Typical air conditioning units installed in land-based buildings, such as homes, schools, or offices, include several standard components: an interior air handler, including evaporator coils and a fan; an exterior condensing unit, including a condensing coil, a compressor, and a fan; and an expansion valve located between the interior air handler and the exterior compressor unit. In general, an interior air handler and an exterior condensing unit work in conjunction by cycling refrigerant throughout the system and changing the state of the refrigerant from liquid to gas, thereby cooling the interior of the building, and exhausting heat outside of the building. These systems may be referred to as “air-to-air” systems because, inside the building, air is blown over serpentine coils of refrigerant to remove/distribute cold air inside the building and, outside the building, air is blown over another set of coils of the same refrigerant to remove heat therefrom.
When an air conditioning system turns on, the interior air handler draws warm ambient air from inside of the building through an air chamber within the air handler. The air passes through a filter to remove impurities, such as dust, and then passes over serpentine evaporator coils, which are filled with cold, compressed, liquid refrigerant. The refrigerant inside the coils absorbs heat as it changes from a liquid to a gaseous state. The cooled air is then exhausted through air ducts throughout the building, thereby cooling individual rooms therein. The warm refrigerant located within the evaporator coils, which is now a gas, is then pumped by the compressor to the exterior condensing unit. When the exterior condensing unit receives the warm, expanded, gaseous refrigerant, the compressor functions to compress the refrigerant, increasing the refrigerant's pressure and significantly increasing its temperature. Simultaneously, a fan located in the exterior condensing unit draws air into the unit, blowing the air over the refrigerant, now located within the condensing coil, thereby cooling the refrigerant and exhausting the heat dissipated by the refrigerant. When the refrigerant cools, it becomes a compressed liquid, which is then pumped back to the interior air handler, and the cycle continues in order to cool the building. During cold weather, an air-to-air system can be reversed to provide heat to the interior of a building.
As opposed to air-to-air systems typically employed in land-based buildings, traditional marine air conditioning systems function quite differently. This is partly out of out of necessity and partly out of resourcefulness. Unlike a house or other building with plenty of room in the attic to run ductwork, space in marine vessels is at a premium. There is usually no room to run large air ducts to carry a large volume of cold air from room to room. For this reason, marine systems generally channel small tubes of cold water around the vessel. In each room, the coils are exposed and air is blown over them, thereby cooling the air and, in turn, the room. The closed system returns the water back to an area where the water is chilled again and the cycle restarts. More specifically, in marine based systems, lines of refrigerant, like the ones described above that would be used to cool a building, are, in marine applications, only used to cool the closed-loop supply of water that runs throughout the boat.
In addition, marine-based air conditioning systems also differ from land-based air conditioning systems because, in marine systems, water, as opposed to air, is used to absorb heat generated by pressurizing refrigerant. To do this, marine vessels take advantage of the cooling medium they rest upon. More specifically, marine systems utilize similar components to that of land-based systems, including a compressor, coils, expansion valve, and fans; however, marine systems use sea or lake water, which is typically drawn into the system from the water source upon which the vessel rests. This relatively cool water is pulled into the vessel, passed over the hot coils, and exhausted back out of the vessel.
Traditional building-based air conditioning units suffer from a number of drawbacks, namely that they consume a high amount of energy, generate a large amount of heat, and circulate long lines of hazardous refrigerant—requiring large volumes of refrigerant within the lines—into and out of a building. While marine-based systems have some advantages, such as shorter lines of refrigerant, these traditional water-based air conditioning units require an external water source for cooling, invariably leading to losses in efficiency. Further, the water used in marine air conditioning units for cooling is typically seawater and requires maintenance.
Therefore, a need exists to overcome the problems with the prior art as discussed above.